Hello, I have successfully installed the mail server...in the Domain List everything is OK and in the green area. The e-mails are only partially sent.
My e-mails are rejected by the big providers (554-web.de (mxweb111) Nemesis ESMTP Service not available 554-No SMTP service 554-Bad DNS PTR resource record).
I cannot receive e-mails. It does not show an error message when sending.
The server is located in Germany (contabo.net - Centos7).
Thanks for helping